1. Waterproof design, specification of sensitivity is 2psi=under0.5 kg/cm2 2. These device can avoid personnel injuries and roller shutter break down when the low limit switch fails. 3. Battery insufficient alarm function. 4. Patent certification. Safety strip - Waterproof design - Anti-Ultra Violet - Clip any length for suiting door - anti-press specification : 2psi, under 0.5 kg/cm2(attested stardart 0.41kg/cm2) Safety pneumatic receiver - Voltage:DC6V - Stanby current:9μ + - 5%